[RFC PATCH v2 01/29] ntsync: Introduce the ntsync driver and character device.

Elizabeth Figura
2024-01-31T02:16:03Z

ntsync uses a misc device as the simplest and least intrusive uAPI interface.

Each file description on the device represents an isolated NT instance, intended
to correspond to a single NT virtual machine.

Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
---
drivers/misc/Kconfig | 9 ++++++++
drivers/misc/Makefile | 1 +
drivers/misc/ntsync.c | 52 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 62 insertions(+)
create mode 100644 drivers/misc/ntsync.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 4fb291f0bf7c..bdd8a71bd853 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -504,6 +504,15 @@ config OPEN_DICE
measured boot flow. Userspace can use CDIs for remote attestation
and sealing.

+config NTSYNC
+ tristate "NT synchronization primitive emulation"
+ help
+ This module provides kernel support for emulation of Windows NT
+ synchronization primitives. It is not a hardware driver.
+
+ To compile this driver as a module, choose M here: the
+ module will be called ntsync.
+
If unsure, say N.

config VCPU_STALL_DETECTOR
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index ea6ea5bbbc9c..153a3f4837e8 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_PVPANIC) += pvpanic/
obj-$(CONFIG_UACCE) += uacce/
obj-$(CONFIG_XILINX_SDFEC) += xilinx_sdfec.o
obj-$(CONFIG_HISI_HIKEY_USB) += hisi_hikey_usb.o
+obj-$(CONFIG_NTSYNC) += ntsync.o
obj-$(CONFIG_HI6421V600_IRQ) += hi6421v600-irq.o
obj-$(CONFIG_OPEN_DICE) += open-dice.o
obj-$(CONFIG_GP_PCI1XXXX) += mchp_pci1xxxx/
diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
new file mode 100644
index 000000000000..e4969ef90722
--- /dev/null
+++ b/drivers/misc/ntsync.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ntsync.c - Kernel driver for NT synchronization primitives
+ *
+ * Copyright (C) 2024 Elizabeth Figura
+ */
+
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+
+#define NTSYNC_NAME "ntsync"
+
+static int ntsync_char_open(struct inode *inode, struct file *file)
+{
+ return nonseekable_open(inode, file);
+}
+
+static int ntsync_char_release(struct inode *inode, struct file *file)
+{
+ return 0;
+}
+
+static long ntsync_char_ioctl(struct file *file, unsigned int cmd,
+ unsigned long parm)
+{
+ switch (cmd) {
+ default:
+ return -ENOIOCTLCMD;
+ }
+}
+
+static const struct file_operations ntsync_fops = {
+ .owner = THIS_MODULE,
+ .open = ntsync_char_open,
+ .release = ntsync_char_release,
+ .unlocked_ioctl = ntsync_char_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+ .llseek = no_llseek,
+};
+
+static struct miscdevice ntsync_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = NTSYNC_NAME,
+ .fops = &ntsync_fops,
+};
+
+module_misc_device(ntsync_misc);
+
+MODULE_AUTHOR("Elizabeth Figura");
+MODULE_DESCRIPTION("Kernel driver for NT synchronization primitives");
+MODULE_LICENSE("GPL");
--
2.43.0